Field of the Invention
The present invention relates to treating zones adjacent a wellbore. More particularly, the invention relates to hydraulically fracturing multiple zones in a single trip.
Description of the Related Art
With extended reach wells, it is common to have multiple hydrocarbon-bearing zones at different locations along the length of a wellbore. In order to increase production at the various zones, they are often “hydraulically fractured.” Hydraulic fracturing is a technique in which a liquid, like water is mixed with sand and chemicals and injected at high pressure into a hydrocarbon-bearing formation (zone) surrounding the wellbore. The resulting small fractures (typically less than 1 mm) permit oil and gas to migrate to the wellbore for collection. Multiple zones at different depths mean multiple fracturing jobs requiring each zone to be isolated from adjacent zones, typically through the use of packers that seal an annular area between the wellbore and a tubular string extending back to the surface of the well.
In some instances, the zones are fractured in separate trips using bridge plugs, resulting in multiple trips and increased costs. In other cases, the zones are treated using ball seats and balls of various sizes, resulting in wellbore debris when the balls are “blown out” to reach a lower zone. What is needed is a more efficient apparatus and methods for treating multiple zones in a single trip.